Seizures and Seizure Planning Flashcards
what are one of the most common neurological conditions seen in veterinary practice?
seizures
how many dogs present with seizures each year?
1 in 125
in what animals are seizures most commonly seen?
dogs but can be seen in cats
if seizures are seen in cats what is the usual cause?
usually secondary to another condition
what are the key considerations that must be made about an owner when their pet has a seizure?
it can be very distressing for the owner especially the first one as they don’t know what is going on
how do neurons transmit information in the normal brain?
through chemical and electrical signals
what are interneurons?
large group of inhibitory cells which regulate the neurons in the brain
how is a seizure caused?
balance between excitatory and inhibitory input is altered leading to hypersynchronisation of neurons and so a seizure
define hypersynchronisation
The excessive synchronization of the firing of neurons that leads to seizures
what is a seizure?
an abnormal, uncontrollable, hypersynchronus electrical activation of a large group of neurons which may produce convulsions, minor physical signs, cognitive disturbances or a combination of symptoms
what is an isolated seizure?
lasts less than 5 mins and animal fully recovers after
what is a cluster seizure?
2 or more seizures within a 24 hour period with complete recovery in between
what type of seizure is a neurological emergency?
status epilepticus
describe status epilepticus
seizure lasting longer than 5 minutes
2 seizures without complete recovery in between (so may seem continuous)
why is status epilepticus dangerous?
brain damage will occur and worsen the longer the seizure goes on
what are the 2 main types of seizure?
partial or focal
generalised (tonic / clonic)
what part of the brain is affected in a partial or focal seizure?
asymmetric - only one side
what are the signs of partial / focal seizures?
facial twitching
hypersalivation
behavioural changes
consciousness maintained
what are the 2 types of partial / focal seizure?
simple
complex
what is the difference between a simple and complex focal / partial seizure?
in simple there is no change in mentation whereas in complex change in mentation is seen
what areas of the brain are involved in generalised (tonic/clonic) seizures?
bilateral cerebral hemisphere involvement
describe what happens during a generalised (tonic/clonic) seizure
autonomic signs (urinate and defecate) loss of consciousness
what are the 3 phases of generalised (tonic/clonic) seizures?
pre-ictal
ictal
post-ictal
how long does the pre-ictal phase last for?
minuites
when does the pre-ictal phase occur?
before the seizure happens
what are the signs of the pre-ictal seizure phase?
may be subtle
behaviour changes
altered mentation
attention seeking behaviour
when does the ictal phase occur?
the actual seizure
what happens during the ictal phase?
loss of consciousness
muscle contraction
urination / defecation
when does the post-ictal phase occur?
after the seizure
how long does the post ictal phase of a seizure last?
minutes to days
depends on individual
what are the signs of the post-ictal phase?
abnormal neurological signs which may be subtle or marked
what are the 2 main extracranial causes of seizures?
toxins
metabolic
what are the main toxins which cause seizures?
methaldehyde (slug bait) ethylene glycol (antifreeze) permethrin (cats) pesticides Ivermectin (collies) human drugs
what are the metabolic causes of seizures?
portosystemic shunt
hypoglycaemia
hypocalcaemia
why can a postosystemic shunt lead to seizures?
change in blood flow will collect toxins from vessels that have been bypassed before shunt placed that are then moved around the body
what are the 2 main intracranial causes of seizures?
structural
functional
what are the structural causes of seizures?
brain tumor
inflammation
hydrocephalus
what is the functional cause of seizures?
idiopathic epilepsy
what is the most common cause of seizures?
idiopathic epilepsy
what age are animals that present with idiopathic epilepsy?
6 months to 6 years
what signs will suggest that an animal has idiopathic epilepsy?
recurrent single seizures normal inter-ictal neuro exam normal metabolic investigation normal brain MRI normal CSF (if tap taken)
how is idiopathic epilepsy / seizure cause diagnosed?
history blood tests MRI scan with contrast CSF analysis video assessment of seizure monitoring and recording (e.g. seizure diary) retinal exam blood pressure (if possible)
what information can be gained when taking a history of a patient with seizures?
is it a true seizure
any history of toxin ingestion, head trauma or meidacation
what blood tests will be used to diagnose the cause of seizures?
haematology
biochem
fasted blood glucose
pre and post prandial bile acids
what contrast is used in MRI scans of the brain?
gadolinium
what is needed when preparing for CSF tap?
clip and surgical prep
what position must the animals head be held in for a CSF tap?
flexed downwards
why is important to know the difference between seizures and seizure mimics/
testing and mediaction are different
what are the main seizure mimic disorders?
narcolepsy/cataplexy fly-catching movement disorder syncope 3rd degree AV block canine epileptoid cramping syndrome peripheral vestibular disease
what is narcolepsy/cataplexy?
sleep wake disorder - limbs will go floppy and animal will suddenly collapse
describe how to identify narcolepsy/cataplexy
collapses are flaccid inherited loss of muscle tone (increased in seizures) no autonomic signs will return to normal straight after
what is the cause of fly-catching?
unknown
what happens during fly-catching?
animal appears as if they are chasing or trying to catch imaginary flies
how long can fly-catching last for?
minutes to hours
is mentation altered during fly catching behaviour?
no - normal
are there autonomic signs associated with fly-catching?
no
describe movement disorder
episodic
patient remains conscious
involuntary movements that are spontaneous and uncontrolled
neurologically normal between episodes
what is syncope often mistaken for?
narcolepsy / cataplexy
what is syncope?
fainting - temporary loss of conciousness
what causes syncope?
reduced oxygenation to the brain which is usually cardiac related
what may cause syncope that is not cardiac related?
neurological
hypoglycaemia
hypocalcaemia
describe how 3rd degree AV block differs from seizures
prolonged hypoxic event
partial seizure like presentation (may be wobbly)
but not actually seizing
what dogs are most commonly affected by canine epileptiod cramping syndrome?
boarder terriers
what is canine eplieptiod cramping syndrome?
movement disorder
describe a canine eplieptiod cramping syndrome presentation
conscious and responsive no autonomic signs normal mentation cramping or stiffness occurs during normal movement
when should emergency seizure management only be performed?
under the guide/instruction of the VS
what is involved in emergency management of the seizing patient?
provide O2 place IV catheter when possible administer diazepam assess circulation and temp intubate if needed provide active cooling if hyperthermic collect full bloods
when will it not be possible to place an IV catheter?
in ictal phase of seizure
how may diazepam be administered to the seizing patient?
IV bolus
rectally
intranasally
what volume of diazepam is given IV in seizing patients?
0.5mg/kg
what volume of diazepam is given rectally in seizing patients?
2mg/kg
what volume of diazepam is given intranasally in seizing patients?
0.5 mg/kg
when may you give mannitol (0.5 mg/kg) to a seizing patient?
IV (slowly) if seizure activity lasts more than 15 minutes or there is reason to suggest cerebral oedema and raised ICP
what should be tested first when bloods are taken from a seizing patient?
glucose, electrolyte and calcium
what should be done if the seizing patient is on phenobarbital?
collect baseline blood sample to assess drug conc. and see if alterations to prescription are needed
what questions should be asked on phone triage to an owner of an animal that’s seizing?
any history of seizures known toxin exposure known head trauma length of seizure how many seizures is the patient conscious and responsive any urination or defecation
when should owners be advised to travel to the practice with their seizing pet?
when safe to do so - wait for recovery or until owner feels able
what are the main considerations when nursing a seizure patient?
area of ward with least noise
lights dimmed wherever possible
bottom kennel
seizure plan on kennel with doses calculated
seizure pack with medication drawn up
sign on door to limit staff member entry and traffic
what is the main goal of the environment around seizure patients?
quiet and calm as possible with as little stimulation as possible to reduce any potential seizure triggers
what should you do if the patient you are caring for seizes?
stay calm note the time inform vet in charge of case and ask for help remove any surrounding dangers dim the lights reduce noise limit handling once safe monitor vital signs if possible follow seizure plan if one in place
what should you not do with a seizing patient?
put your hands in or near their mouth
what must you try to get from the owner when they are calling with an emergency?
contact number in case you are cut off
what should you do when a seizing patient arrives in hospital?
reassure the owner triage - ABC O2 therapy IV access ASAP anticonvulsants check temp active cooling if hyperthermia mannitol, CRI and intubation if needed
what is the aim of seizure management in an emergency?
stop the patient seizuring
what is the aim of seizure management for recurrent seizures?
improve QOL for owner and patient
reduce seizure frequency
reduce severity
balance acceptable levels of side effects and cost
what is essential for recurrent seizure management?
owner education and compliance
what is the first line of treatment for medical management of idiopathic epilepsy?
Phenobarbitol (Epiphen)
what receptors does Phenobarbitol work at?
barbituate that acts on GABA receptors in the brain
how does phenobarbital have it’s effect?
increases frequency of synaptic inhibition and reduces neuronal excitability
what are the benefits of Phenobarbital?
high efficacy
high safety
low cost
how long does it take for plasma Phenobarbitol concentration to reach steady state?
~2 weeks
what is the significance of steady state drug plasma concentration?
the level of drug required in the plasma to exert full effect
why does Phenobarbital require regular blood tests?
to check steady state plasma conc
what are the side effects of Phenobarbital?
hepatotoxicity with high doses sedation polydipsia polyuria polyphagia ataxia
what symptoms usually decrease after the fist few weeks on Phenobarbital?
sedation
polydipsia
polyuria
polyphagia
what drugs are used for medical management of idiopathic epilepsy?
Phenobarbital (Epiphen)
Potassium bromide (Libromide)
Levetiracetam (Keppra)
Imepitoin (Pexion)
when is Potassium bromide often used?
used as first line AED or in conjunction with another AED
what is the most common use of potassium bromide?
in conjunction with another AED
what is the role of Potassium bromide?
reduced neuronal excitability
how long does it take to achieve steady state plasma concentration of Potassium bromide?
~4 months
how is Potassium bromide excreted?
renally - care in compromised patinets
what is the issue with Potassium bromide in cats?
can cause serious lung issues
what are the side effects of Potassium bromide?
gastric irritation nausea polydipsia polyuria sedation pancreatitis
what is the method of action of Levtiracetam (Keppra)?
unknown
what is Levtiracetam (Keppra) used for?
adjunct to other AEDs
why is Levtiracetam (Keppra) safe for patients with kidney disease?
primarily excreted unchanged in the urine
how is Levtiracetam (Keppra) excreted?
unchanged via the kidneys
what are the advantages of Levtiracetam (Keppra)?
excellent oral bioavailability
well tolerated with few side effects
safe for kidney patients
what are the side effects of Levtiracetam (Keppra)?
ataxia
vomiting
sedation
what is Imepitoin (Pexion) licenced for?
idiopathic epilepsy only
what receptors does Imepitoin (Pexion) act on?
GABA receptors
how does Imepitoin (Pexion) work?
reduced electrical activity of GABA receptors
what animals should not be given Imepitoin (Pexion)?
dogs with impaired hepatic function, renal or cardiovascular disorders
what are the side effects of Imepitoin (Pexion)?
ataxia
vomiting
polyphagia
what other AEDs may be used to manage seizures?
gabapentin
diazepam
zonisimide
(all less effectie)
what are the main home care considerations for seizure patients?
manage owner expectations family situation financial situation type of property communication build client trust and a rapport encourage repeat visits
what must be considered about family situation when creating a seizure home care plan?
work patterns
children (drugs and distress from seizures)
ability to administer medication on time and reliably
what must be considered about financial situation when creating a seizure home care plan?
medication is lifelong
there will be repeated blood tests and consults
medication may be altered and added to
what must be considered about the type of property when creating a seizure home care plan?
access for patient
is garden safe (e.g. steps they could fall down)
what must be considered about communication when creating a seizure home care plan?
involve the whole family inculding children
what are the main things to consider offering to clients with a seizure dog in terms of support?
nursing consultations after initial diagnosis
follow up calls to check in
written communication
support groups / evening sessions for clients
